Toggle press



Dec. 7, 1954 H. G. HECHT TOGGLE PRESS Filed Oct. 4, 1951 United States Patent O ToGGLE PRESS Helmut 'Gottfried Hecht, Goeppingen, Germany, assignor to ttol-ermann May, Schwaebisch Gmuend, Germany Application October 4, 1951, Serial No. 249,656

Claims priority, application Germany October 4, 1950 3 Claims. (Cl. 100-282) The present invention relates to a toggle press having a specially arranged toggle linkage and constituting an improvement uponthe'toggle presses which are described in U. S. Patent 2,600,242, dated lune l0, 1952.

In former toggle presses (excluding those shown in said patent), the toggles were ordinarily arranged so that the distance between the fulcrum and' movable pins increased during the power strokes with a resulting force which was resisted by stresses in the press frame above the table or platen. This resulted in the requirement for large cross-sectional areas and over-all dimensions of the presses, which considerably increased their weight, regardless of the type, especially in the case of open-gap presses.

LThese disadvantages of the former toggle presses are eliminated according to Patent 2,600,242 by arranging the toggle system in such a manner that a movable pin is free to move with respect to the fulcrum pin during the power stroke, so as to relieve the press frame of the disadvantageous stresses. As described in said patent, an advantageous form of this toggle system is achieved by arranging it with a comparatively long bell crank forming a'part of the toggle which may also be favorably positioned to clear the throat of the press so as to obtain a compact arrangement of the toggle linkage in the press ram, whereby the size of the press unit may be reuce It is one of the objects of the present invention to provide an improved arrangement of the fulcrum and moving pins of the toggle linkage with respect to the platen in this type of toggle press.

Another object of the present invention is to provide a toggle linkage in which the line of action of the link connecting fulcrum and moving pins is substantially at right angles to the surface of the platen when the toggle linkage is in extended position.

A further object of the present invention is to arrange the entire drive below the platen in the lower part of the press frame.

An additional object of the press is to arrange two toggle linkages for balanced action on both sides of the press frame.

The novel features which are considered as characteristic of the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a side view of my new toggle press;

Fig. 2 is a section taken on the line 2 2 of Fig. 1; and,

Fig. 3 is a fragmentary section of the lower part of the press frame taken on the line 3 3 of Fig. 2.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawlngs.

Referring to Figs. 1 to 3, there is shown a ram slide 203 slidably arranged in guide portions 202 of a press frame 222 with the guide arranged at right angles to the plane of a table 201 of the toggle press. On the table 201 a platen 246 is removably mounted. The ram slide 203 is equipped with a moving pin 234, the center line of which is numbered 209. The moving pin 234 is rotatably supported in two sleeves 233 provided in the ram slide. The pin carries on both sides moving pin links 205 of curved rice shape. On both sides of the guide portions 202 slots 235 are provide in a direction parallel to the main axis of the press frame, said slots serving to guide guiding blocks 236 during the motion of the ram slide 203. At its lower end the ram slide 203 carries a tool holder arrangement 243. Underneath and on both sides of the press table 201 fulcrum pins 237 are provide. The axes 204 of these pins determine the fulcrums of the toggle linkages. The fulcrum pins 237 are upwardly and reactively supported by two projections 238 of the press table 201. rl`he projecting ends of said fulcrurn pins 237 are mounted in supporting plates 239 fastened to the press projections 238` by screws 244.

The aforementioned moving pin links 205 are pivoted by means of knee joint pins 240 to double-joint fulcrum links 206 which encompass in a fork-like manner the moving pin links 205 and are at their other ends rotatably arrangedon the above mentioned fulcrum pins 237. The axes of pins 240 are numbered 208. A fulcrum line is represented by that part of each double-joint fulcrum link 206 which connects its fulcruin pin center 204 with the knee joint center 208. Pivoted to the double-joint links 206, by means of pins 241, are connecting rods 216, the latter being pivoted with their other ends to the crank pins 221 of outside cranks 217.

As shown in Figs. -2 and 3, the drive is transmitted from a motor 220 through a coupling 245 to a pinion 242 mountedV with its shaft in the press frame 222 and meshing with a toothed gear 232. Fixedly arranged on the shaft to which the gear 232 is rigidly connected, is a toothed gear 231 which meshes with a toothed gear 230 (see Fig. 3) rigidly mounted on the shaft of crank 217. The clutch for starting and stopping the press is not shown in the drawing, since such are well known.

The operation of the press will now be described in connection with Figs. 1 and 2:

ln Fig. l the heavy dash lines indicate the relationships between centers or axes 204, 208 and 209 when the slide 203 is in its top position and the crank pins 221 are at rearward dead center positions, i. e., opposite to the forward position in which they are illustrated in solid lines.

The toggle links are then arranged in such a manner that` the knee joint axis 20S is in its extreme outer or rearward position, the acute angle between the lines of action of the moving pin links 205 and the fulcrum links 206 being a maximum a and the crank pins 221 being at their rearward dead center. When the cranks 217 rotate with the motion being transmitted from motor 220, the connecting rods 216 pull the knee joint pins 240 in forward direction until the crank pins 221 arrive at their forward dead centers shown in solid lines in Fig. l. Now the acute angle between the toggle links 205 and 206 is a minimum, as indicated at a and the ram slide 203 is in its bottom position. The lines of action of the moving pin links 205, i. e., the lines connecting the axis 209 of the moving pin 234 with the axes 208 of the knee joints are substantially at right angles to the surface of the table 201 or platen 246 respectively. Since the toggle systems are not entirely extended in this position, the fulcrum centers 204 do not lie on the lines between centers 208 and 209 but are at a small distance therefrom.

As shown in Fig. 3, the entire drive is located below the table 201, an arrangement which allows of making the overall height of the press comparatively small.

It will be observed that the main structural parts of the frame are arranged with the slide 203, the platen 246 and the transmission inside the frame, whereas the linkages constituted by the members 205, 206, 216 and 217 are outside the frame.

While the invention has been illustrated and described by way of the foregoing embodiments, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

For example, the ram slide 203 and its gaiide in frame 222 may be of rectangular or essentially square cross section, rather than circular.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications kwithout omitting features that, from the 3 standpoint of prior art, fairly constitute essential characteristics of the generic or specic aspects of this invention'and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalents of the following claims.

I claim:

1. A toggle press comprising an upright frame, a worksupporting platen therein, a ram guide carried by theframe above and normal to the platen, a ram slide in the guide, portions of the frame on opposite sides of the platen extending to the guide, said portions having openings therein, pin means extending from the slide through said openings respectively, means on the frame below and on opposite sides of the platen providing a pair of coaxial fulcrum pivots, a pair of depending fulcrum pin links carried by said fulcrum pivots, said pin links being provided with coaxial knee joints and with additional coaxial pivots, a pair of first connecting rods extending from said pin means to said coaxial knee joints on the pin links, rotary cranks on the frame having coaxial crank pins, a pair of second connecting rods connected to and extending from said crank pins to said pair of coaxial pivots on the fulcrum pin links, transmission means for driving said cranks, the arrangement being such that when the ram slide is advanced toward the platen its maximum amount, a straight line drawn between the center of the knee joint pivot on the pin link and the pin means on the slide will be substantially perpendicular to the plane of the platen.

2. A toggle press made according to claim l, wherein both linkages constituted by all of the respective connecting rods, fulcrum pin links and cranks are located on the exterior of the frame, said ram slide, platen and transmission means being located interiorly of the frame.

3. A toggle press comprising an upright frame, a worksupporting platen therein, a ram guide carried by the frame and located above the platen, a ram slide in the guide movable perpendicularly with respect to said platen, said ram guide having openings adjacent said ram slide, pin means extending from the slider through said openings, means on the frame on opposite sides of the platen providing a pair of coaxial fulcrum pivots, a pair of depending fulcrum pin links carried by said fulcrum pivots, said pin links being provided With coaxial knee joints located at a level below the platen, a pair of connecting rods extending from said pin means to said coaxial knee joints on the fulcrum pin links, driving means on the frame adapted simultaneously to oscillate said fulcrum pin links, the arrangement being such that when the ram slide is advanced toward the platen its maximum amount, a straight line drawn between the center of the knee joint pivot on the pin link and the pin means on the slide will be substantially perpendicular to the plane of the platen and the said line will form an acute angle with the said plane of the platen in all other positions of the slide.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 38,013 Seeley Mar. 24, 1863 2,269,389 Weida Ian. 6, 1942 2,271,771 Klocke Feb. 3, 1942 2,600,242 May June l0, 1952 FOREIGN PATENTS Number Country Date 271,725 Switzerland Feb. 16, 1951 414,69() Great Britain Aug. 7, 1934 601,690 Germany Aug. 22, 1934 

